For proper operation, the lubricating oil for an automotive internal combustion engine should be changed regularly, because the oil becomes dirty and less viscous, making it less effective in protecting the engine against wear. It is also a regular practice to change the oil filter when the oil is changed, because the oil filter becomes dirty as the oil becomes dirty. Unfortunately, after an engine's oil and filter have been changed, the engine usually is only slightly lubricated, because the oil changing procedure results in most of the new oil being located in the sump of the engine, with the filter empty. As a result, when the engine is initially started up after an oil change, a short span of time exists before sufficient operating oil pressure is developed during which the filter is filled by the engine oil pump--a time span during which the engine is without proper lubrication, causing excessive wear of the engine. It has been estimated that a typical engine could last at least 20% longer before wearing out if oil could be supplied immediately to the engine upon start-up after each oil change.
The prior art has dealt extensively with the problem of the immediate lubrication needs of an engine after start-up. The prior art has attempted to solve the problem by providing auxiliary lubrication systems. Carter U.S. Pat. No. 3,295,507, which uses an auxiliary electric oil pump, is typical. The Carter lubrication system utilizes the auxiliary pump, which is attached to the oil sump, to generate sufficient oil pressure when the ignition key is turned but before the engine is started. Of course, the system will inherently charge a newly installed oil filter. A filter adaptor attaching the oil filter to the engine block is connected to the auxiliary pump. The adaptor contains a pressure sensor which indicates to the driver by means of an indicator light that sufficient oil pressure has been generated by the auxiliary pump to allow startup of the engine. Other prior art systems have used pressurized oil reservoirs that discharge oil into the engine before start-up. These also will inherently charge a newly installed oil filter. Typical of these kinds of systems is Waldecker U.S. Pat. No. 3,422,807, which discloses an oil reservoir mounted on an engine. When the engine starter switch is closed, the reservoir discharges oil into the engine to temporarily lubricate it until the engine oil pump generates sufficient oil pressure. The reservoir is filled by the lubrication system after start-up in preparation for the next start-up. Still other devices include packaged oil filters which are precharged with oil.
The prior art solutions to the engine lubrication problem have several drawbacks. First, they add unnecessary equipment and expense to the engine. Auxiliary pumps, oil lines and reservoirs take up valuable space in an already cramped modern engine compartment and add to the present high cost of an automobile. Second, the prior art systems increase complexity, adding to the number of parts that can malfunction in a modern engine. In addition, the prior art systems add weight to the engine, a very undesirable result at a time when automotive manufacturers strive to make their products lighter and more fuel efficient. Precharged oil filters are costly, messy to install, and cannot be readily installed on engines where the apertured base of the oil filter faces downwardly.